– Ibn Hibban mentioned him in Thiqat (Trustworthy ones), and said: “One of the Imams of the world, he narrates from Abu al Waleed and the people of Iraq.” (10)
– Ya’qub al Qarrab said: “I have not seen the like of Uthman b. Sa`id neither has he seen the like of himself. He studied Literature under Ibn Al-A’rabi, Fiqh under Abu Ya’qub al-Buwaiti, and Hadith from Yahya bin Ma’een and Ali bin al Madini. He was leading in these sciences, may Allah have mercy on him.”
– Muhammad bin al Mundhir said: “I heard Abu Zur’ah Ar-Razi, and I asked him about Uthman bin Saeed, so he said:’ He has been gifted in authoring fine works.’ ”
– Abul-Fadl al-Jarudi said: “He was an Imam to be followed in his lifetime and after his death.”Al-Hasan bin Saheb Ash-Shashi said: “I asked Abu Dawud As-Sijistani (11) about Uthman bin Saeed, so he said: ‘ From him we learned Hadith.’ ” (12)Abu Hamid Al-A’mashi said: “I have not seen from the Muhaditheen anyone like Muhammad bin Yahya, Uthman bin Saeed [Ad-Darimi], and Ya’qbu bin Sufyan.” (13)

Abu Uthman As-Sabuni narrated with his own chain that Imam Qutaibah bin Saeed said at the end of his book “al Iman”:
“If you see a man loving Sufyan Ath-Thawri, Malik bin Anas, Al-Awza’i…” and he mentioned a number of Imams, then he said: “Then know that He is upon the Sunnah.” Then Abu Uthman As-Sabuni said: “And I added to those that Qutaibah rahimahulllah mentioned: That whomever loves them, he is upon the Sunnah, from the Imam of Hadith whom are to be followed, and to be upon their guidance… from them are: Muhammad bin Idrees Ash-Shafi’i…” and he mentioned a number of scholars, from them was: Uthman bin Saeed Ad-Darimi. (14)

Adh-Dhahabi said about him: “The Imam, Allamah, the Hafidh, the Critic … he was persevere upon the Sunnah, and well-versed in debating.”
He also said: “Uthman ad-Darimi was like a tree trunk in the eyes of the innovators’ (15), and it was said that he is the one who stood up against Muhammad bin Karram – whom the sect al-Karramiyah are attributed to – and exiled him from Herat.” (16)

Taj Ad-Deen As-Subki said about him: “One of the Trustworthy scholars, and whom was mentioned by Al-Abbadi in his “Tabaqat” saying: ‘ The Imam of Hadith and Fiqh…) (17)

Al-Hasan Ahmad bin Muhammad bin Abdoos said:
“When I wanted to travel to Uthman bin Saeed Ad-Darmi, I came to Abu Bakr Muhammad b. Ishaq b. Khuzaimah, and I asked him to write to him for me, so he wrote to him. I entered Herat in Rabee’ al Awwal, 280 H. I went to Uthman bin Saeed, and delivered the letter to him. He read it and welcomed me, and asked me how Abu Bakr Ibn Khuzaimah was doing, then he said to me: ‘When did you arrive?’
I said: Tomorrow.
He said: ‘My son, go back to them, for you haven’t come yet.’
so I got embarrassed.
Then he said: ‘ Don’t be shy my son, for I have resided in your country for two years, and your shaikhs at that time were able to bear from me things like this.’ ” (18)

– Istiwa and Allah’s Elevation:
He said:
“And the Muslims have agreed that Allah is above His Throne, above His Heavens.” (23)
“And we knew, with no doubt, that Allah is above His Throne, above His Heavens, like He described Himself, separate from His creation.” (24)
“For Allah Tabaraka wa Ta’la is above His Throne, above His Heavens, separate from His creation, so whoever doesn’t know Him like this, then he doesn’t know His God Whom he worships.” (25)
He said in regards to Allah’s saying -translation of the meaning-: {And Pharoah said, “O Haman, construct for me a tower that I might reach the ways * The ways of the heavens, so that I may look at the God (Ilah) of Moses, but indeed, I think he is a liar.”}[40:36-37] :
“In these ayat is a clear explanation, and an obvious indicator that Musa was calling Fir’awn (Pharoah) to know that Allah is above the heaven, and because of that, he (Fir’awn) ordered to build a big tower, and wanted to see Him (Allah Ta’ala).” (26)

Allah being with His creation -Ma`iyyah-:
He said: «Some of them said: Let’s put aside the interpretation of scholars, we only depended on the Quran for evidence, so bring the Book of Allah. We said: ‘yes … however, you are ignorant of its meaning, so strayed from the straight path, and you clung to the middle of the ayah, and deliberately overlooked its beginning and its ending, because Allah –Azza wa Jal- began the verse with His knowledge of them, and ended it with that, He said: {Have you not seen that Allah knows whatsoever is in the heavens and whatsoever is on the earth? There is no Najwa (secret counsel) of three, but He is their fourth…} until His saying: {and afterwards on the Day of Resurrection, He will inform them of what they did. Verily, Allah is the All-Knower of everything}, so this is evidence that He meant His knowledge of them and their deeds, not that He Himself is in every place with them as you claim.» (27)

On Tashbih in Allah’s Attributes:
He said:«As there is nothing like Him (Allah), thus there is no hand like His Hand.» (28)«As there is nothing like Him, there is no hearing like His Hearing, nor sight like His Sight, and there is nothing in creation that they can be compared, or likened or resembled to.» (29)«All of these ahadeeth, and even more than it, mention the descending of the Lord, Most High; and the people of Fiqh and knowledge from our scholarly teachers are upon believing in them; none of them deny any of these ahadeeth or refrained from narrating them until this group (i.e. jahmiyyah) appeared, who then opposed the ahadeeth of the Messenger of Allah and expended great effort to oppose them, so they questioned: ‘How does He descend?’, to which we replied: ‘We were not commanded to know how He descends in our Religion, and our minds cannot comprehend/grasp it, and there is no creation that is equal to Him that we may equate His acts or attributes with.» (30)

On Seeing Allah in the Hereafter:
«When Allah put a restriction for seeing Him in the Hereafter with His saying: {Looking (ila) at their Lord (Allâh)} (i.e. with the preposition “ila” which means to/towards), we knew that it is the seeing of the eyes.» (31)